Buggy code:
public class ComposerView extends AbstractFrameView { public static final String ACCOUNTINFOPANEL = "accountinfopanel" ; private JSplitPane rightSplitPane ; public ComposerView ( AbstractFrameController controller ) { } public void setRightDividerLocation ( int i ) { } public int getRightDividerLocation ( ) { } public void init ( ) { super . init ( ) ; Container contentPane ; contentPane = getContentPane ( ) ; ComposerController controller = ( ( ComposerController ) ( frameController ) ) ; if ( isAccountInfoPanelVisible ( ) ) toolbarPane . add ( controller . getIdentityInfoPanel ( ) ) ; rightSplitPane = new JSplitPane ( JSplitPane . HORIZONTAL_SPLIT ) ; rightSplitPane . setBorder ( null ) ; rightSplitPane . add ( controller . getHeaderController ( ) . view , JSplitPane . LEFT ) ; rightSplitPane . add ( controller . getAttachmentController ( ) . view , JSplitPane . RIGHT ) ; rightSplitPane . setDividerSize ( 5 ) ; rightSplitPane . setDividerLocation ( 400 ) ; JPanel topPanel = new JPanel ( ) ; <START_BUG> topPanel . setBorder ( BorderFactory . createEmptyBorder ( 0 , 5 , 0 , 0 ) ) ; <END_BUG> JLabel subjectLabel = new JLabel ( MailResourceLoader . getString ( "dialog" , "composer" , "subject" ) ) ; subjectLabel . setDisplayedMnemonic ( MailResourceLoader . getMnemonic ( "dialog" , "composer" , "subject" ) ) ; JLabel smtpLabel = new JLabel ( MailResourceLoader . getString ( "dialog" , "composer" , "identity" ) ) ; smtpLabel . setDisplayedMnemonic ( MailResourceLoader . getMnemonic ( "dialog" , "composer" , "identity" ) ) ; JLabel priorityLabel = new JLabel ( MailResourceLoader . getString ( "dialog" , "composer" , "priority" ) ) ; priorityLabel . setDisplayedMnemonic ( MailResourceLoader . getMnemonic ( "dialog" , "composer" , "priority" ) ) ; GridBagLayout gridbag = new GridBagLayout ( ) ; topPanel . setLayout ( gridbag ) ; GridBagConstraints c = new GridBagConstraints ( ) ; c . anchor = GridBagConstraints . WEST ; c . gridx = 0 ; c . gridy = 0 ; c . weightx = 0.0 ; c . insets = new Insets ( 0 , 0 , 5 , 5 ) ; gridbag . setConstraints ( smtpLabel , c ) ; topPanel . add ( smtpLabel ) ; c . gridx = 1 ; c . weightx = 1.0 ; gridbag . setConstraints ( controller . getAccountController ( ) . view , c ) ; topPanel . add ( controller . getAccountController ( ) . view ) ; c . gridwidth = GridBagConstraints . RELATIVE ; c . gridx = 2 ; c . weightx = 0.0 ; gridbag . setConstraints ( priorityLabel , c ) ; topPanel . add ( priorityLabel ) ; c . gridwidth = GridBagConstraints . REMAINDER ; c . gridx = 3 ; gridbag . setConstraints ( controller . getPriorityController ( ) . view , c ) ; topPanel . add ( controller . getPriorityController ( ) . view ) ; c . gridx = 0 ; c . gridy = 1 ; c . gridwidth = GridBagConstraints . RELATIVE ; gridbag . setConstraints ( subjectLabel , c ) ; topPanel . add ( subjectLabel ) ; c . fill = GridBagConstraints . HORIZONTAL ; c . gridx = 1 ; c . gridy = 1 ; c . gridwidth = GridBagConstraints . REMAINDER ; c . weightx = 1.0 ; gridbag . setConstraints ( controller . getSubjectController ( ) . view , c ) ; topPanel . add ( controller . getSubjectController ( ) . view ) ; JPanel editorPanel = new JPanel ( ) ; editorPanel . setBorder ( null ) ; editorPanel . setLayout ( new BorderLayout ( ) ) ; JScrollPane scrollPane = new JScrollPane ( controller . getEditorController ( ) . view ) ; editorPanel . add ( scrollPane , BorderLayout . CENTER ) ; JPanel centerPanel = new JPanel ( ) ; centerPanel . setBorder ( BorderFactory . createEmptyBorder ( 0 , 0 , 0 , 0 ) ) ; centerPanel . setLayout ( new BorderLayout ( ) ) ; centerPanel . add ( topPanel , BorderLayout . NORTH ) ; centerPanel . add ( editorPanel , BorderLayout . CENTER ) ; JPanel mainPanel = new JPanel ( ) ; mainPanel . setLayout ( new BorderLayout ( ) ) ; mainPanel . add ( rightSplitPane , BorderLayout . NORTH ) ; mainPanel . add ( centerPanel , BorderLayout . CENTER ) ; contentPane . add ( mainPanel , BorderLayout . CENTER ) ; pack ( ) ; } protected Menu createMenu ( AbstractFrameController controller ) { } protected ToolBar createToolbar ( AbstractFrameController controller ) { } public void loadWindowPosition ( ) { } public IdentityInfoPanel getAccountInfoPanel ( ) { } public void showToolbar ( ) { } public void showAccountInfoPanel ( ) { } public boolean isAccountInfoPanelVisible ( ) { } }

Fix:
topPanel . setBorder ( BorderFactory . createEmptyBorder ( 5 , 5 , 0 , 0 ) ) ;